John Langdon Brooks

Bio: John Langdon Brooks is an academic researcher from Yale University. The author has contributed to research in topics: Daphnia & Darwinism. The author has an hindex of 8, co-authored 14 publications receiving 3667 citations.

Predation, Body Size, and Composition of Plankton

Abstract: ARTICLES Organic Fluorine Chemistry: C. G. Krespai.................................. Expanding rapidly, the science of these compounds has assumed both theoretical and practical importance. The Biological Synthesis of Cholesterol: K. Bloch .............................. Predation, Body Size, and Con-mposition of Plankton: J. L. Brooks and S. I. Dodson ... The effect of a marine planktivore on lake plankton illustrates theory of size, competition, and predation. 7

Speciation in ancient lakes.

Abstract: UR knowledge of the geographical aspects of speciation is based primarily upon the distribution of species and subspecies of terrestrial nimals, especially birds. An observer on a broad continental area is accustomed to finding a single species occupying one particular ecological niche over that large area wherein the niche is available. Over some regions of the land surface the niches of a given kind are linearly arranged, as for instance in the narrow lowland strip between the mountains and the sea which makes up the greater part of the western coast of North America. In this geographical situation an observer is impressed by the fact that representatives of a species inhabiting the entire linear strip have a different appearance, depending upon which part or small section of the strip they live in. The fox sparrows of North America illustrate the effect of the arrangement of habitats, in a way beautifully worked out by Swarth (1920). All the fox sparrows belong to a single species Passerella iliaca. Those of eastern North America breed over the entire forested area of Canada, and in Newfoundland and northern Alaska as well. Although differences can be noted between birds taken from the eastern and western ends of the range, they are minor and unworthy of nomenclatural recognition. All are considered to belong to the typical subspecies. Fox sparrows also find the west coast of North America habitable and breed from the proximal Aleutian Islands south to the Olympic Peninsula in Washington. Within this coastal strip there is considerable variation of the fox sparrows in coloration (from bright reddish-brown to clear gray), in relative lengths of feet and tail, and in size and shape of the bill. Six subspecies have been named from limited areas along this strip. However, there is complete intergradation between five of these subspecies, and those areas of transition from one subspecies to another within a short space are taken as the boundaries of adjacent subspecies. There do not appear to be any physical barriers within these regions of transition different from those within the range of any one subspecies. The fox sparrows which breed on Kodiak Island are different from either of the two subspecies on adjacent parts of the Alaskan Coast, from which they are, of course, isolated and constitute a separate subspecies insularis. Aside from the northwestern corner of the state of Washington, which is inhabited by the southernmost members of this chain, the only zones habitable by fox sparrows in the western United States cover the upper slopes of mountains. These habitable areas become smaller and more isolated to the southward. The subspecies with the largest ranges are: fulva, which breeds throughout central Oregon and the northeastern corner of California; mariposae, whose breeding colonies are scattered throughout he north and central parts of the Sierra Nevada; and schistacea, which breeds in the Rockies from Alberta to Nevada and eastward into eastern Wyoming. The subspecies with more limited ranges occur to the south and the west of these wider-ranging subspecies: brevicauda breeds in a restricted area in the Coast Range in north central California; and monoensis and canescens are each confined to limited areas on the eastern slopes of the Sierra Nevada, in the central part of California near the Nevada border. The population of each of these two areas has diverged just enough to be recognized taxonomically, whereas the population of fox sparrows in several isolated mountain areas exhibit insufficient morphological distinctions and are grouped in the subspecies stephensi. References to the latter two types of habitat distribution, viz., the linear arrangement and the highly isolated types, are readily available in ornithological literature. Mayr (1942) has quoted several. One example to which I wish to direct at-

Predation, Body Size, and Composition of Plankton

Abstract: ARTICLES Organic Fluorine Chemistry: C. G. Krespai.................................. Expanding rapidly, the science of these compounds has assumed both theoretical and practical importance. The Biological Synthesis of Cholesterol: K. Bloch .............................. Predation, Body Size, and Con-mposition of Plankton: J. L. Brooks and S. I. Dodson ... The effect of a marine planktivore on lake plankton illustrates theory of size, competition, and predation. 7

The ontogenetic niche and species interactions in size-structured populations

Abstract: Body size is manifestly one of the most important attributes of an organism from an ecological and evolutionary point of view. Size has a predominant influence on an animal's energetic requirements, its potential for resource exploitation, and its susceptibility to natural enemies. A large literature now exists on how physiological, life history, and population parameters scale with body dimensions (24, 131). The ecological literature on species interactions and the structure of animal communities also stresses the importance of body size. Differences in body size are a major means by which species avoid direct overlap in resource use (153), and size-selective predation can be a primary organizing force in some communities (20, 70). Size thus imposes important constraints on the manner in which an organism interacts with its environment and influences the strength, type, and symmetry of interactions with other species (152, 207). Paradoxically, ecologists have virtually ignored the implications of these observations for interactions among species that exhibit size-distributed populations. For instance, it has been often suggested that competing species